Farr, D-Carmel, captured 72.28 percent of the vote in Santa Cruz County, 55.68 percent in Santa Clara County, 60.57 percent in Monterey County and 55.24 percent in San Benito County with all precincts reported.

His closest challenger was Republican Jeff Taylor in the four counties. Farr and Taylor will advance to the Nov. 6 general election.

Farr, 70, had represented the 17th Congressional District until the political boundaries were redrawn with data from the 2010 U.S. Census. He is now vying to represent the 20th Congressional District.

It includes all of Monterey and San Benito counties, parts of Santa Cruz County and portions of southern Santa Clara County around Gilroy.

Anna Eshoo, D-Menlo Park, also held on to her House seat.

Eshoo garnered 63.90 percent of the vote in Santa Cruz County and 58.41 percent of the vote in Santa Clara County. In San Mateo County, Eshoo had 66.82 percent of the vote compared with her closest challenger, Republican Dave Chapman, with 27.5 percent of the vote.

Chapman also trailed in second place in the other two counties. As the top two vote-getters, Chapman and Eshoo will appear on November's ballot.

"It is enormously gratifying to have the support of so many of my new constituents, and the continuing trust of those I've been serving," Eshoo said. "I'll do everything I can to give my constituents the representation they deserve."

First elected in 1992, Eshoo, 69, is the ranking Democrat on a House subcommittee focused on communication and technology.

Her district includes Scotts Valley and the San Lorenzo Valley, the North Coast, and the mountains above Santa Cruz, including part of the Forest of Nisene Marks State Park.

Eshoo has introduced bills to ensure shoppers get accurate information about smartphones and another that requires broadband networks to be built during new road construction. She also has been a backer of President Obama's health care overhaul.

Farr has served on the powerful Appropriations Committee since 1999.

He said during the campaign that his main policy areas have been the economy, the environment and education.

He is the top Democrat on the Subcommittee on Agriculture, Rural Development, Food and Drug Administration and Related Agencies.